1. Field of the Invention
The present invention relates generally to monitoring characteristics of a flow path and, more particularly, to monitoring a flow path which includes solid components such as, for example, grain or other components of a harvested plant material.
2. State of the Art
Combine harvesters are conventionally used in harvesting a wide variety of crop materials. Such combine harvesters may be used to cut a crop or plant material from the field or, they may be used to collect a crop or plant material which has already been cut and arranged in what is known as a windrow within the crop field. Upon collection of the crop or plant material, the material is conventionally passed through a threshing and separating mechanism of the combine harvester to separate the grain therefrom. The grain, along with other impurities such as, for example, chaff, dust, leaves or other straw particles, is fed to a cleaning mechanism to further clean and separate the grain from such impurities. Such a cleaning mechanism might include one or more sieves with an air stream directed therethrough to assist in the removal of chaff and residual straw.
The grain, now separated and cleaned from the crop material, is collected and temporarily stored in a grain tank located on the combine harvester while the residual material (i.e., material other than grain) is conventionally discharged from the combine harvester back onto the crop field. In some combine harvesters the residual material may be “rethreshed” such as by processing it through another threshing and separating mechanism to increase the amount of grain recovered.
The residual materials, such as the straw and chaff, may be discharged from the combine harvester in scattered manner for reintroduction into the soil as a nutrient therefor, or they may be discharged in a narrow row for subsequent collection by another machine. For example, a baler may pass across the field to collect and package (bale) the discharged residual material.
As a practical matter, the harvesting of grain or some other crop material is not a completely efficient process. In other words, some of the material being harvested (e.g., the grain) may be discharged with what is considered to be the residual plant material. Various grain-loss sensors have been developed in the past in an effort to determine the amount of grain being discharged with residual plant material. Conventionally, such sensors have included a piezoelectric transducer which is configured to produce an electrical signal in response the impingement of a material upon a surface of the sensor. Such sensors have been placed, for example, at the discharge end of a cleaning mechanism, to determine whether kernels of grain are intermixed with the residual plant material which is being discharged from the combine harvester.
Generally, such a piezoelectric sensor has been employed in an effort to detect the impingement of a component having a minimum specified mass while remaining unaffected by other materials exhibiting a mass below the specified minimum. Thus, for example, it was intended that a grain kernel would be detected by the sensor while residual material such as straw, leaves, etc., would not be detected by the sensor due to their relative lack of mass in comparison with the grain kernel. However, such sensors do not necessarily provide an accurate indication of the amount of grain being discharged, or otherwise processed, with residual plant materials. Rather, such piezoelectric grain loss sensors often do not distinguish between, for example, a grain kernel and a large piece of straw. Thus, the electrical signal generated by such a sensor may inaccurately indicate that a significant amount of grain is being discharged with the residual material. Such an indication may persuade an operator of the combine harvester to change one or more operating parameters thereof. The changes made to the any operating parameters in response to the indications of the grain loss sensor may, thus, be improper and cause the combine harvester to operate inefficiently.
While various attempts have been made to improve such grain loss sensors, there remains a need to provide an accurate grain loss sensor which properly discriminates and differentiates between multiple components (e.g., between grain kernels and straw) within a flow path and which provides an accurate indication of the same.
Thus, in view of the shortcomings in the art, it would be advantageous to provide a method and apparatus for accurately monitoring one or more characteristics of a flow path which includes a solid component flowing therethrough. It would further be advantageous to utilize such a method and apparatus in conjunction, for example, with a combine harvester to optimize the production of such a harvester such that the desired component of a crop or plant material may be more efficiently harvested.